1. Field of the Invention
The present invention relates to disk drives. More particularly, the present invention relates to a sensor system for improving write operations for a hard disk drive (HDD).
2. Description of the Related Art
FIG. 1 shows an exemplary hard disk drive (HDD) 100 having a magnetic read/write (R/W) head (or a recording slider) 101 that includes, for example, a tunnel-valve read sensor, that is positioned over a selected track on a magnetic disk 102. As the fly-height of slider 101 becomes smaller, the chance of slider 101 hitting asperities on disk 102, for example, disk defects, particles, and/or lubricant bumps, becomes greater, resulting in a higher probability of fly-height modulation, i.e., “slider jump-up”. When fly-height modulation occurs during a write process, that portion of data being written during slider jump-up can be lost because the data is not properly written on the disk due to greater than expected write-head-to-disk distance. There is no current technique available for detecting fly-height modulation during a write process. Consequently, write processes are performed essentially “blind” with the hope that the data is properly written on the disk.
Conventional approaches for minimizing slider modulation include minimization of head-disk interaction by, for example, reducing the take-off height of a disk, reducing the number of particles, and using less mobile lubricant on the disk. These approaches, however, will reach their respective limits for minimizing head-disk interaction as slider fly-height is further reduced.
Consequently, what is needed is a technique for detecting slider fly-height modulation during a write process. Further, what is needed is a technique for inhibiting a write operation when slider fly-height modulation is detected.